The present invention relates generally to a position-sensing device and more particularly to an inexpensive position-sensing device that may include other types of sensors.
It is extremely useful to be able to automatically and continually identify the location of an object or a person, particularly if this can be done inexpensively. Imagine a week from now is your first wedding anniversary. Due to business reasons, you suddenly are called to travel to a remote site, thousands of miles away from your spouse. She is terribly annoyed by your absence. It is an important day. Fortunately, immediately after arrival at the site, you have succeeded in getting her some very nice gifts. An express service promises that she will get the gifts exactly on the anniversary day, which is four days from now. Wouldn't it give you the peace of mind if you could periodically track the location of the package during the next four days? Four days later, assuming that the gifts will be arriving at your home in the next twenty minutes, wouldn't she be thrilled if she gets an intimate call from you, and during the call, the gifts arrive right at her doorsteps? She probably will forgive you for not being with her during the first wedding anniversary. There may even be some pleasant surprises waiting for you when you get home!
Let's step back and assume that the gifts include a pair of exotic fruits from the Orient. You know your spouse has never tasted such fruits before and she would love to taste them. You also know it is going to take four days before the gifts reach your house. To keep their freshness, the fruits have to be refrigerated during the trip at a temperature below 50 degree Fahrenheit. The express service guarantees that your gifts will be kept at low temperature, not higher than 45 degrees. You constantly worry that the power to the refrigerator may be accidentally turned off, causing the temperature to gradually go up, and mining the fruits. Wouldn't you be willing to pay a small price if the express service provides a feature where your pager would beep if the ambient temperature of your gifts goes above 45 degrees? This will then allow you to immediately call the express service and sound the alarm.
Even if what have been described is technologically feasible, it would probably be prohibitively expensive. One of the critical barriers is the position sensor indicating the location of the gifts. A typical global-positioning system (GPS) receiver, such as one in a car, costs about two thousand dollars (US$2000.00). A handheld GPS system for hiking costs more than two hundred and fifty dollars (US$250.00). The auto manufacturers may be able to afford to have such an expensive item for vehicle navigation of automobiles. It is inconceivable to expect common citizens to be able to afford such a device.
In addition, the sizes of the systems can be an annoying factor. You don't want the systems to be a few times larger in size or heavier in weight than your gifts. The cost of transport will then be predominately due to the systems. Imagine you are using Federal Express to send your company brochure—a few ounces—to a customer. It is unreasonable to attach a four-pound GPS system to the Federal Express package. One way to get around this hurdle is wait till there is a critical mass accumulated before shipping to a destination. But, customers go for an express service because they want speedy delivery, and thus are probably not willing to wait.
It should be apparent from the foregoing that there is a genuine need for an inexpensive position-sensing device. Such a device would probably be suitable for many more applications if it has a small form factor.